@article {53581, title = {Acoustic signalling of aggressive intent in the agonistic encounters of female Asian particoloured bats}, journal = {Animal Behaviour}, volume = {149}, year = {2019}, month = {Jan-03-2019}, pages = {65 - 75}, abstract = {

The signals of animal aggressive intent can communicate aggression levels to competitors, thereby settling conflicts at an early stage and thus reducing energy costs. We tested whether aggressive vocalizations of female Asian particoloured bats, Vespertilio sinensis, encode aggressive intent during agonistic encounters that occur whenever an intruder pushes a resident to obtain a more central roosting spot. Our results showed that the number of noisy/tonal syllables of the disturbed bats met the three criteria used to define aggressive intent. First, the number and ratio of tonal syllables were significantly greater when intruders continued to push, and the number and ratio of noisy syllables were significantly greater when they stopped pushing (context criterion). Second, skin temperature related to emotional arousal during aggressive interaction generally increased when intruders stopped pushing but was unchanged or decreased when they continued pushing (predictive criterion). Finally, bats preferentially selected stimuli with more tonal syllables, and they spent more time approaching more noisy syllables in a two-choice playback experiment (response criterion). Thus, we propose that the number of noisy/tonal syllables within aggressive vocalizations of female Asian particoloured bats functions to signal aggressive intent.

}, keywords = {aggressive intent, aggressive vocalizations, skin temperature}, issn = {00033472}, doi = {10.1016/j.anbehav.2019.01.012}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0003347219300132}, author = {Zhao, Xin and Jiang, Tinglei and Liu, Heng and Wang, Yuze and Liu, Ying and Feng, Jiang} } @article {53527, title = {Bats increase vocal amplitude and decrease vocal complexity to mitigate noise interference during social communication}, journal = {Animal Cognition}, year = {2019}, month = {Oct-01-2019}, abstract = {

Natural background noises are common in the acoustic environments in which most organisms have evolved. Therefore, the vocalization and sound perception systems of vocal animals are inherently equipped to overcome natural background noise. Human-generated noises, however, pose new challenges that can hamper audiovocal communication. The mechanisms animals use to cope with anthropogenic noise disturbances have been extensively explored in a variety of taxa. Bats emit echolocation pulses primarily to orient, locate and navigate, while social calls are used to communicate with conspecifics. Previous studies have shown that bats alter echolocation pulse parameters in response to background noise interference. In contrast to high-frequency echolocation pulses, relatively low-frequency components within bat social calls overlap broadly with ambient noise frequencies. However, how bats structure their social calls in the presence of anthropogenic noise is not known. Here, we hypothesized that bats leverage vocal plasticity to facilitate vocal exchanges within a noisy environment. To test this hypothesis, we subjected the Asian particolored bat, Vespertilio sinensis, to prerecorded traffic noise. We observed a significant decrease in vocal complexity (i.e., an increased frequency of monosyllabic calls) in response to traffic noise. However, an increase in the duration and frequency of social calls, as have been observed in other species, was not evident. This suggests that signal simplification may increase communication efficacy in noisy environments. Moreover, V. sinensis also increased call amplitude in response to increased traffic noise, consistent with the predictions of the Lombard effect.

}, keywords = {acoustic communication, bats, Noise, Social calls, vocal plasticity}, issn = {1435-9448}, doi = {10.1007/s10071-018-01235-0}, url = {http://link.springer.com/10.1007/s10071-018-01235-0}, author = {Jiang, Tinglei and Guo, Xiong and Lin, Aiqing and Wu, Hui and Sun, Congnan and Feng, Jiang and Kanwal, Jagmeet S.} } @article {50497, title = {Social calls honestly signal female competitive ability in Asian particoloured bats}, journal = {Animal Behaviour}, volume = {127}, year = {2017}, month = {Jan-05-2017}, pages = {101 - 108}, abstract = {

Why a variety of social animals vocalize during agonistic foraging interactions remains obscure. One possibility is that these signals advertise the signaller\&$\#$39;s competitive ability, playing a role in the defence of food resources, yet there is limited evidence in support of this idea. Here, we used adult female Asian particoloured bats, Vespertilio sinensis, to test whether individual variation in competitive ability when foraging can be explained by social calls. Using synchronized infrared video and audio recording, we monitored bat social vocalizations, dominance rank and weight gain in triads under controlled food conditions. Additionally, subsequent playbacks, consisting of experimental stimuli, echolocation pulses and silence, were presented to feeding bats in a laboratory. Analyses showed that females uttered low-frequency social calls composed of one to five syllable types during feeding competition. The rates of social vocalizations increased with reduced food availability. Interestingly, dominance score and weight gain correlated weakly with body size, but positively with call rate and associated parameters. Playback of social calls inhibited the visits of bats to the focal food dish compared to playback of silence and echolocation pulses. The amount of food consumed was greatly reduced in the presence of experimental stimuli versus controls. Collectively, these results highlight that acoustic signals serve as an honest indicator of bat competitive ability.

}, keywords = {aggressive interaction, bats, competitive ability echolocation, foraging, social call}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.03.012}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347217300842}, author = {Luo, Bo and Lu, Guanjun and Chen, Kelly and Guo, Dongge and Huang, Xiaobin and Liu, Ying and Feng, Jiang} }